Since wife is already earning and if her earning is sufficient for her then she shall not be entitled to maintenence. Child is joint liability of both parents so child expenses are to be shared by both parents. Since your earning is higher so major portion may be contributed by you. Payment of EMI for car shall be counted as your income being asset construction, however, payment of rent for parents who too are your liability so that would be deducted while calculating your income. Rest depend upon merit snd circumstances of the case.